package jdomain.util;

import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.lang.reflect.Constructor;
import java.lang.reflect.Field;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;

/**
 * BrowserLauncher is a class that provides one static method, openURL, which
 * opens the default web browser for the current user of the system to the given
 * URL. It may support other protocols depending on the system -- mailto, ftp,
 * etc. -- but that has not been rigorously tested and is not guaranteed to
 * work.
 * <p>
 * Yes, this is platform-specific code, and yes, it may rely on classes on
 * certain platforms that are not part of the standard JDK. What we're trying to
 * do, though, is to take something that's frequently desirable but inherently
 * platform-specific -- opening a default browser -- and allow programmers (you,
 * for example) to do so without worrying about dropping into native code or
 * doing anything else similarly evil.
 * <p>
 * Anyway, this code is completely in Java and will run on all JDK 1.1-compliant
 * systems without modification or a need for additional libraries. All classes
 * that are required on certain platforms to allow this to run are dynamically
 * loaded at runtime via reflection and, if not found, will not cause this to do
 * anything other than returning an error when opening the browser.
 * <p>
 * There are certain system requirements for this class, as it's running through
 * Runtime.exec(), which is Java's way of making a native system call.
 * Currently, this requires that a Macintosh have a Finder which supports the
 * GURL event, which is true for Mac OS 8.0 and 8.1 systems that have the
 * Internet Scripting AppleScript dictionary installed in the Scripting
 * Additions folder in the Extensions folder (which is installed by default as
 * far as I know under Mac OS 8.0 and 8.1), and for all Mac OS 8.5 and later
 * systems. On Windows, it only runs under Win32 systems (Windows 95, 98, and NT
 * 4.0, as well as later versions of all). On other systems, this drops back
 * from the inherently platform-sensitive concept of a default browser and
 * simply attempts to launch Netscape via a shell command.
 * <p>
 * This code is Copyright 1999-2001 by Eric Albert (ejalbert@cs.stanford.edu)
 * and may be redistributed or modified in any form without restrictions as long
 * as the portion of this comment from this paragraph through the end of the
 * comment is not removed. The author requests that he be notified of any
 * application, applet, or other binary that makes use of this code, but that's
 * more out of curiosity than anything and is not required. This software
 * includes no warranty. The author is not repsonsible for any loss of data or
 * functionality or any adverse or unexpected effects of using this software.
 * <p>
 * Credits: <br>
 * Steven Spencer, JavaWorld magazine ( <a
 * href="http://www.javaworld.com/javaworld/javatips/jw-javatip66.html">Java Tip
 * 66 </a>) <br>
 * Thanks also to Ron B. Yeh, Eric Shapiro, Ben Engber, Paul Teitlebaum, Andrea
 * Cantatore, Larry Barowski, Trevor Bedzek, Frank Miedrich, and Ron Rabakukk
 * 
 * @author Eric Albert ( <a
 *         href="mailto:ejalbert@cs.stanford.edu">ejalbert@cs.stanford.edu </a>)
 * @version 1.4b1 (Released June 20, 2001)
 */
public class BrowserLauncher {

   /**
    * The Java virtual machine that we are running on. Actually, in most cases
    * we only care about the operating system, but some operating systems
    * require us to switch on the VM.
    */
   private static int jvm;

   /** The browser for the system */
   private static Object browser;

   /**
    * Caches whether any classes, methods, and fields that are not part of the
    * JDK and need to be dynamically loaded at runtime loaded successfully.
    * <p>
    * Note that if this is <code>false</code>,<code>openURL()</code> will
    * always return an IOException.
    */
   private static boolean loadedWithoutErrors;

   /** The com.apple.mrj.MRJFileUtils class */
   private static Class mrjFileUtilsClass;

   /** The com.apple.mrj.MRJOSType class */
   private static Class mrjOSTypeClass;

   /** The com.apple.MacOS.AEDesc class */
   private static Class aeDescClass;

   /** The <init>(int) method of com.apple.MacOS.AETarget */
   private static Constructor aeTargetConstructor;

   /** The <init>(int, int, int) method of com.apple.MacOS.AppleEvent */
   private static Constructor appleEventConstructor;

   /** The <init>(String) method of com.apple.MacOS.AEDesc */
   private static Constructor aeDescConstructor;

   /** The findFolder method of com.apple.mrj.MRJFileUtils */
   private static Method findFolder;

   /** The getFileCreator method of com.apple.mrj.MRJFileUtils */
   private static Method getFileCreator;

   /** The getFileType method of com.apple.mrj.MRJFileUtils */
   private static Method getFileType;

   /** The openURL method of com.apple.mrj.MRJFileUtils */
   private static Method openURL;

   /** The makeOSType method of com.apple.MacOS.OSUtils */
   private static Method makeOSType;

   /** The putParameter method of com.apple.MacOS.AppleEvent */
   private static Method putParameter;

   /** The sendNoReply method of com.apple.MacOS.AppleEvent */
   private static Method sendNoReply;

   /** Actually an MRJOSType pointing to the System Folder on a Macintosh */
   private static Object kSystemFolderType;

   /** The keyDirectObject AppleEvent parameter type */
   private static Integer keyDirectObject;

   /** The kAutoGenerateReturnID AppleEvent code */
   private static Integer kAutoGenerateReturnID;

   /** The kAnyTransactionID AppleEvent code */
   private static Integer kAnyTransactionID;

   /** The linkage object required for JDirect 3 on Mac OS X. */
   //private static Object linkage;

   /** The framework to reference on Mac OS X */
   //private static final String JDirect_MacOSX = "/System/Library/Frameworks/Carbon.framework/Frameworks/HIToolbox.framework/HIToolbox";

   /** JVM constant for MRJ 2.0 */
   private static final int MRJ_2_0 = 0;

   /** JVM constant for MRJ 2.1 or later */
   private static final int MRJ_2_1 = 1;

   /** JVM constant for Java on Mac OS X 10.0 (MRJ 3.0) */
   private static final int MRJ_3_0 = 3;

   /** JVM constant for MRJ 3.1 */
   private static final int MRJ_3_1 = 4;

   /** JVM constant for any Windows NT JVM */
   private static final int WINDOWS_NT = 5;

   /** JVM constant for any Windows 9x JVM */
   private static final int WINDOWS_9x = 6;

   /** JVM constant for any other platform */
   private static final int OTHER = -1;

   /**
    * The file type of the Finder on a Macintosh. Hardcoding "Finder" would keep
    * non-U.S. English systems from working properly.
    */
   private static final String FINDER_TYPE = "FNDR";

   /**
    * The creator code of the Finder on a Macintosh, which is needed to send
    * AppleEvents to the application.
    */
   private static final String FINDER_CREATOR = "MACS";

   /** The name for the AppleEvent type corresponding to a GetURL event. */
   private static final String GURL_EVENT = "GURL";

   /**
    * The first parameter that needs to be passed into Runtime.exec() to open
    * the default web browser on Windows.
    */
   private static final String FIRST_WINDOWS_PARAMETER = "/c";

   /** The second parameter for Runtime.exec() on Windows. */
   private static final String SECOND_WINDOWS_PARAMETER = "start";

   /**
    * The third parameter for Runtime.exec() on Windows. This is a "title"
    * parameter that the command line expects. Setting this parameter allows
    * URLs containing spaces to work.
    */
   private static final String THIRD_WINDOWS_PARAMETER = "\"\"";

   /**
    * The shell parameters for Netscape that opens a given URL in an
    * already-open copy of Netscape on many command-line systems.
    */
   private static final String NETSCAPE_REMOTE_PARAMETER = "-remote";
   private static final String NETSCAPE_OPEN_PARAMETER_START = "'openURL(";
   private static final String NETSCAPE_OPEN_PARAMETER_END = ")'";

   /**
    * The message from any exception thrown throughout the initialization
    * process.
    */
   private static String errorMessage;
   private static String outMessage;
   private static String command;

   /**
    * An initialization block that determines the operating system and loads the
    * necessary runtime data.
    */
   static {
      loadedWithoutErrors = true;
      String osName = System.getProperty( "os.name" );
      Log.debug( "os.name=" + osName );
      if ( osName.startsWith( "Mac OS" ) ) {
         String mrjVersion = System.getProperty( "mrj.version" );
         String majorMRJVersion = mrjVersion.substring( 0, 3 );
         try {
            double version = Double.valueOf( majorMRJVersion ).doubleValue();
            if ( version == 2 ) {
               jvm = MRJ_2_0;
            }
            else if ( version >= 2.1 && version < 3 ) {
               // Assume that all 2.x versions of MRJ work the same. MRJ 2.1
               // actually
               // works via Runtime.exec() and 2.2 supports that but has an
               // openURL() method
               // as well that we currently ignore.
               jvm = MRJ_2_1;
            }
            else if ( version == 3.0 ) {
               jvm = MRJ_3_0;
            }
            else if ( version >= 3.1 ) {
               // Assume that all 3.1 and later versions of MRJ work the same.
               jvm = MRJ_3_1;
            }
            else {
               loadedWithoutErrors = false;
               errorMessage = "Unsupported MRJ version: " + version;
            }
         }
         catch ( NumberFormatException nfe ) {
            loadedWithoutErrors = false;
            errorMessage = "Invalid MRJ version: " + mrjVersion;
         }
      }
      else if ( osName.startsWith( "Windows" ) ) {
         if ( osName.indexOf( "9" ) != -1 ) {
            jvm = WINDOWS_9x;
         }
         else {
            jvm = WINDOWS_NT;
         }
      }
      else {
         jvm = OTHER;
      }

      if ( loadedWithoutErrors ) { // if we haven't hit any errors yet
         loadedWithoutErrors = loadClasses();
      }
   }

   /**
    * This class should be never be instantiated; this just ensures so.
    */
   private BrowserLauncher() {
   }

   /**
    * Called by a static initializer to load any classes, fields, and methods
    * required at runtime to locate the user's web browser.
    * 
    * @return <code>true</code> if all intialization succeeded
    *         <code>false</code> if any portion of the initialization failed
    */
   private static boolean loadClasses() {
      switch ( jvm ) {
         case MRJ_2_0:
            try {
               Class aeTargetClass = Class.forName( "com.apple.MacOS.AETarget" );
               Class osUtilsClass = Class.forName( "com.apple.MacOS.OSUtils" );
               Class appleEventClass = Class
                     .forName( "com.apple.MacOS.AppleEvent" );
               Class aeClass = Class.forName( "com.apple.MacOS.ae" );
               aeDescClass = Class.forName( "com.apple.MacOS.AEDesc" );

               aeTargetConstructor = aeTargetClass
                     .getDeclaredConstructor( new Class[] { int.class } );
               appleEventConstructor = appleEventClass
                     .getDeclaredConstructor( new Class[] { int.class,
                           int.class, aeTargetClass, int.class, int.class } );
               aeDescConstructor = aeDescClass
                     .getDeclaredConstructor( new Class[] { String.class } );

               makeOSType = osUtilsClass.getDeclaredMethod( "makeOSType",
                     new Class[] { String.class } );
               putParameter = appleEventClass.getDeclaredMethod(
                     "putParameter", new Class[] { int.class, aeDescClass } );
               sendNoReply = appleEventClass.getDeclaredMethod( "sendNoReply",
                     new Class[] {} );

               Field keyDirectObjectField = aeClass
                     .getDeclaredField( "keyDirectObject" );
               keyDirectObject = (Integer) keyDirectObjectField.get( null );
               Field autoGenerateReturnIDField = appleEventClass
                     .getDeclaredField( "kAutoGenerateReturnID" );
               kAutoGenerateReturnID = (Integer) autoGenerateReturnIDField
                     .get( null );
               Field anyTransactionIDField = appleEventClass
                     .getDeclaredField( "kAnyTransactionID" );
               kAnyTransactionID = (Integer) anyTransactionIDField.get( null );
            }
            catch ( ClassNotFoundException cnfe ) {
               errorMessage = cnfe.getMessage();
               return false;
            }
            catch ( NoSuchMethodException nsme ) {
               errorMessage = nsme.getMessage();
               return false;
            }
            catch ( NoSuchFieldException nsfe ) {
               errorMessage = nsfe.getMessage();
               return false;
            }
            catch ( IllegalAccessException iae ) {
               errorMessage = iae.getMessage();
               return false;
            }
            break;
         case MRJ_2_1:
            try {
               mrjFileUtilsClass = Class.forName( "com.apple.mrj.MRJFileUtils" );
               mrjOSTypeClass = Class.forName( "com.apple.mrj.MRJOSType" );
               Field systemFolderField = mrjFileUtilsClass
                     .getDeclaredField( "kSystemFolderType" );
               kSystemFolderType = systemFolderField.get( null );
               findFolder = mrjFileUtilsClass.getDeclaredMethod( "findFolder",
                     new Class[] { mrjOSTypeClass } );
               getFileCreator = mrjFileUtilsClass.getDeclaredMethod(
                     "getFileCreator", new Class[] { File.class } );
               getFileType = mrjFileUtilsClass.getDeclaredMethod(
                     "getFileType", new Class[] { File.class } );
            }
            catch ( ClassNotFoundException cnfe ) {
               errorMessage = cnfe.getMessage();
               return false;
            }
            catch ( NoSuchFieldException nsfe ) {
               errorMessage = nsfe.getMessage();
               return false;
            }
            catch ( NoSuchMethodException nsme ) {
               errorMessage = nsme.getMessage();
               return false;
            }
            catch ( SecurityException se ) {
               errorMessage = se.getMessage();
               return false;
            }
            catch ( IllegalAccessException iae ) {
               errorMessage = iae.getMessage();
               return false;
            }
            break;
         case MRJ_3_0:
            try {
               Class linker = Class.forName( "com.apple.mrj.jdirect.Linker" );
               Constructor constructor = linker
                     .getConstructor( new Class[] { Class.class } );
               /*linkage =*/ constructor
                     .newInstance( new Object[] { BrowserLauncher.class } );
            }
            catch ( ClassNotFoundException cnfe ) {
               errorMessage = cnfe.getMessage();
               return false;
            }
            catch ( NoSuchMethodException nsme ) {
               errorMessage = nsme.getMessage();
               return false;
            }
            catch ( InvocationTargetException ite ) {
               errorMessage = ite.getMessage();
               return false;
            }
            catch ( InstantiationException ie ) {
               errorMessage = ie.getMessage();
               return false;
            }
            catch ( IllegalAccessException iae ) {
               errorMessage = iae.getMessage();
               return false;
            }
            break;
         case MRJ_3_1:
            try {
               mrjFileUtilsClass = Class.forName( "com.apple.mrj.MRJFileUtils" );
               openURL = mrjFileUtilsClass.getDeclaredMethod( "openURL",
                     new Class[] { String.class } );
            }
            catch ( ClassNotFoundException cnfe ) {
               errorMessage = cnfe.getMessage();
               return false;
            }
            catch ( NoSuchMethodException nsme ) {
               errorMessage = nsme.getMessage();
               return false;
            }
            break;
         default:
            break;
      }
      return true;
   }

   /**
    * Attempts to locate the default web browser on the local system. Caches
    * results so it only locates the browser once for each use of this class per
    * JVM instance.
    * 
    * @return The browser for the system. Note that this may not be what you
    *         would consider to be a standard web browser; instead, it's the
    *         application that gets called to open the default web browser. In
    *         some cases, this will be a non-String object that provides the
    *         means of calling the default browser.
    */
   private static Object locateBrowser() {
      if ( browser != null ) {
         return browser;
      }
      switch ( jvm ) {
         case MRJ_2_0:
            try {
               Integer finderCreatorCode = (Integer) makeOSType.invoke( null,
                     new Object[] { FINDER_CREATOR } );
               Object aeTarget = aeTargetConstructor
                     .newInstance( new Object[] { finderCreatorCode } );
               Integer gurlType = (Integer) makeOSType.invoke( null,
                     new Object[] { GURL_EVENT } );
               Object appleEvent = appleEventConstructor
                     .newInstance( new Object[] { gurlType, gurlType, aeTarget,
                           kAutoGenerateReturnID, kAnyTransactionID } );
               // Don't set browser = appleEvent because then the next time we
               // call
               // locateBrowser(), we'll get the same AppleEvent, to which we'll
               // already have
               // added the relevant parameter. Instead, regenerate the
               // AppleEvent every time.
               // There's probably a way to do this better; if any has any
               // ideas, please let
               // me know.
               return appleEvent;
            }
            catch ( IllegalAccessException iae ) {
               browser = null;
               errorMessage = iae.getMessage();
               return browser;
            }
            catch ( InstantiationException ie ) {
               browser = null;
               errorMessage = ie.getMessage();
               return browser;
            }
            catch ( InvocationTargetException ite ) {
               browser = null;
               errorMessage = ite.getMessage();
               return browser;
            }
         case MRJ_2_1:
            File systemFolder;
            try {
               systemFolder = (File) findFolder.invoke( null,
                     new Object[] { kSystemFolderType } );
            }
            catch ( IllegalArgumentException iare ) {
               browser = null;
               errorMessage = iare.getMessage();
               return browser;
            }
            catch ( IllegalAccessException iae ) {
               browser = null;
               errorMessage = iae.getMessage();
               return browser;
            }
            catch ( InvocationTargetException ite ) {
               browser = null;
               errorMessage = ite.getTargetException().getClass() + ": "
                     + ite.getTargetException().getMessage();
               return browser;
            }
            String[] systemFolderFiles = systemFolder.list();
            // Avoid a FilenameFilter because that can't be stopped mid-list
            for ( int i = 0; i < systemFolderFiles.length; i++ ) {
               try {
                  File file = new File( systemFolder, systemFolderFiles[i] );
                  if ( !file.isFile() ) {
                     continue;
                  }
                  // We're looking for a file with a creator code of 'MACS' and
                  // a type of 'FNDR'. Only requiring the type results in
                  // non-Finder
                  // applications being picked up on certain Mac OS 9 systems,
                  // especially German ones, and sending a GURL event to those
                  // applications results in a logout under Multiple Users.
                  Object fileType = getFileType.invoke( null,
                        new Object[] { file } );
                  if ( FINDER_TYPE.equals( fileType.toString() ) ) {
                     Object fileCreator = getFileCreator.invoke( null,
                           new Object[] { file } );
                     if ( FINDER_CREATOR.equals( fileCreator.toString() ) ) {
                        browser = file.toString(); // Actually the Finder, but
                        // that's OK
                        return browser;
                     }
                  }
               }
               catch ( IllegalArgumentException iare ) {
                  errorMessage = iare.getMessage();
                  return null;
               }
               catch ( IllegalAccessException iae ) {
                  browser = null;
                  errorMessage = iae.getMessage();
                  return browser;
               }
               catch ( InvocationTargetException ite ) {
                  browser = null;
                  errorMessage = ite.getTargetException().getClass() + ": "
                        + ite.getTargetException().getMessage();
                  return browser;
               }
            }
            browser = null;
            break;
         case MRJ_3_0:
         case MRJ_3_1:
            browser = ""; // Return something non-null
            break;
         case WINDOWS_NT:
            browser = "cmd.exe";
            break;
         case WINDOWS_9x:
            browser = "command.com";
            break;
         case OTHER:
         default:
            browser = "netscape";
            break;
      }
      return browser;
   }

   /**
    * Attempts to open the default web browser to the given URL.
    * 
    * @param url
    *           The URL to open
    * @throws IOException
    *            If the web browser could not be located or does not run
    */
   public static void openURL( String url ) throws IOException {

      if ( !loadedWithoutErrors ) {
         throw new IOException( "Exception in finding browser: " + errorMessage );
      }
      Object browser1 = locateBrowser();
      if ( browser1 == null ) {
         throw new IOException( "Unable to locate browser: " + errorMessage );
      }
      ProcessHelper helper;
      switch ( jvm ) {
         case MRJ_2_0:
            Object aeDesc = null;
            try {
               aeDesc = aeDescConstructor.newInstance( new Object[] { url } );
               putParameter.invoke( browser1, new Object[] { keyDirectObject,
                     aeDesc } );
               sendNoReply.invoke( browser1, new Object[] {} );
            }
            catch ( InvocationTargetException ite ) {
               throw new IOException(
                     "InvocationTargetException while creating AEDesc: "
                           + ite.getMessage() );
            }
            catch ( IllegalAccessException iae ) {
               throw new IOException(
                     "IllegalAccessException while building AppleEvent: "
                           + iae.getMessage() );
            }
            catch ( InstantiationException ie ) {
               throw new IOException(
                     "InstantiationException while creating AEDesc: "
                           + ie.getMessage() );
            }
            finally {
               aeDesc = null; // Encourage it to get disposed if it was
               // created
               browser1 = null; // Ditto
            }
            break;
         case MRJ_2_1:
            Runtime.getRuntime().exec( new String[] { (String) browser1, url } );
            break;
         case MRJ_3_0:
            int[] instance = new int[1];
            int result = ICStart( instance, 0 );
            if ( result == 0 ) {
               int[] selectionStart = new int[] { 0 };
               byte[] urlBytes = url.getBytes();
               int[] selectionEnd = new int[] { urlBytes.length };
               result = ICLaunchURL( instance[0], new byte[] { 0 }, urlBytes,
                     urlBytes.length, selectionStart, selectionEnd );
               if ( result == 0 ) {
                  // Ignore the return value; the URL was launched successfully
                  // regardless of what happens here.
                  ICStop( instance );
               }
               else {
                  throw new IOException( "Unable to launch URL: " + result );
               }
            }
            else {
               throw new IOException(
                     "Unable to create an Internet Config instance: " + result );
            }
            break;
         case MRJ_3_1:
            try {
               openURL.invoke( null, new Object[] { url } );
            }
            catch ( InvocationTargetException ite ) {
               throw new IOException(
                     "InvocationTargetException while calling openURL: "
                           + ite.getMessage() );
            }
            catch ( IllegalAccessException iae ) {
               throw new IOException(
                     "IllegalAccessException while calling openURL: "
                           + iae.getMessage() );
            }
            break;
         case WINDOWS_NT:
            // Add quotes around the URL to allow ampersands and other special
            // characters to work.
            helper = new ProcessHelper( new String[] { (String) browser1,
                  FIRST_WINDOWS_PARAMETER, SECOND_WINDOWS_PARAMETER,
                  THIRD_WINDOWS_PARAMETER, '"' + url + '"' } );
            helper.execute();
            break;
         case WINDOWS_9x:
            // without third_windows_parameter

            helper = new ProcessHelper( new String[] { (String) browser1,
                  FIRST_WINDOWS_PARAMETER, SECOND_WINDOWS_PARAMETER,
                  '"' + url + '"' } );
            helper.execute();
            break;
         case OTHER:
            // Assume that we're on Unix and that Netscape is installed

            // First, attempt to open the URL in a currently running session of
            // Netscape
            helper = new ProcessHelper( new String[] {
                  (String) browser1,
                  NETSCAPE_REMOTE_PARAMETER,
                  NETSCAPE_OPEN_PARAMETER_START + url
                        + NETSCAPE_OPEN_PARAMETER_END } );
            helper.execute();
            break;
         default:
            // This should never occur, but if it does, we'll try the simplest
            // thing possible
            helper = new ProcessHelper( new String[] { (String) browser1, url } );
            helper.execute();
            break;
      }
   }

   /**
    * Methods required for Mac OS X. The presence of native methods does not
    * cause any problems on other platforms.
    */
   private native static int ICStart( int[] instance, int signature );

   private native static int ICStop( int[] instance );

   private native static int ICLaunchURL( int instance, byte[] hint,
         byte[] data, int len, int[] selectionStart, int[] selectionEnd );

   public static String getErrorMessage() {
      return errorMessage;
   }

   public static String getOutMessage() {
      return outMessage;
   }

   public static String getCommand() {
      return command;
   }


   private static final class ProcessHelper {
      private final String[] args;

      public ProcessHelper( String[] args ) {
         this.args = args;
         StringBuffer buf = new StringBuffer();
         final int len = args.length;
         for ( int i = 0; i < len; i++ ) {
            if ( i > 0 ) {
               buf.append( ' ' );
            }
            buf.append( args[i] );
         }
         command = buf.toString();
      }

      private String readStream( InputStream in ) throws IOException {
         int available = in.available();
         if ( available > 0 ) {
            byte[] data = new byte[available];
            in.read( data );
            return new String( data );
         }
         return null;
      }

      public int execute() {
         try {
            Process process = Runtime.getRuntime().exec( args );
            process.waitFor();
            int result = process.exitValue();
            errorMessage = readStream( process.getErrorStream() );
            outMessage = readStream( process.getInputStream() );

            return result;
         }
         catch ( Exception e ) {
            return -1;
         }
      }
   }
}